The total length of the product is 33mm, the length of the chuck is 20mm, the outer diameter of the bottom is about 9mm, the inner diameter is 5 mm, and the chuck can clamp tools with a shaft diameter of 0.3 to 3.4 mm. This micro self-tightening chuck is compatible with most rotary tools, such as electric micro drills, electric sanders, etc., for drilling, model making, jewelry processing, polishing and grinding, etc. The chuck is made of brass material, which has excellent wear resistance and corrosion resistance, and can withstand high-frequency use and complex working environments. This chuck adopts a self-tightening design. Users only need to simply rotate to firmly clamp the drill bit, which is simple and quick to operate. Packing list: 2x chuck, 2x connecting rod, 2x hexagonal wrench., Manufacturer: Briny River